1. Field of the Invention
This invention relates to exit finding systems and more particularly to exit finding systems that are both tactilely and visually effective when illumination is adequate and tactilely effective when it is not.
2. Prior Art
The exit finding systems of present commercial aircraft are the overhead and exit-proximal signs and the floor lighting, the latter intended to satisfy 14 CFR 25.811(c), "Means must be provided to assist the occupants in locating the exits in conditions of dense smoke.", when the former are obscured by that smoke. While floor lighting clearly addresses situations in which the signs are obscured by smoke but the floor lighting is not, it clearly fails to address situations in which the floor lighting is obscured by smoke, eye irritation, or visual impairment, or in which the floor lighting system itself fails.
Thus any self-guiding system expected to be effective both when vision is compromised and when it is not must also invoke some other sense, and such systems are found in facilities for the blind, where tactiovisual aids abound, and tactiovisual lavatory signs, to cite one example, serve the blind tactilely and the sighted visually. Such aids, however, are not intended for, and will not effectively serve persons whose vision is compromised by eye irritants and smoke, and who must find an exit while crawling "on all fours" in an attempt to get below the heaviest concentrations of smoke and toxic gases, and must find that exit before these gases take their deadly toll.
Tactiovisual aids are also familiar items in aircraft cockpits, where critical knobs, switches, actuators and controls are so coded in the hope of preventing a catastrophe caused by a pilot inadvertently "pressing the wrong button". Tactiovisual exit finding aids are not found in aircraft cabins, however, although such aids could save lives by facilitating evacuation when vision dependent exit finding aids are obscured by smoke.